Radiographic apparatus



June 27, 1950 A. NEMET 2,513,248

RADIOGRAPHIC APPARATUS Filed Dec. 3, 1945 INVENTOR.

BYhBW ATTORNEY Patented June 27, 1950 RADIOGRAPHIC APPARATUS Anthony Nemet, London, England, assignor to The Hartford National Bank & Trust Company, Hartford, Conn, as trustee Application December 3, 1945, Serial No. 632,354 In Great Britain July 12, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires July 12, 1964 3 Claims.

This invention relates to radiographic apparatus and is more particularly but not exclusively applicable to apparatus for miniature radiography.

Apparatus designed for mass miniature radiography in which the image obtained on a fluorescent screen is photographed on a much reduced scale, usually on film as used in miniature cinematography, is often capable of being converted to ordinary full-size radiography. For this purpose the fluorescent screen is replaced or covered by a full-size cassette containing the X-ray film (e. g. 14" x 17 or 15" x 12" film) and, in addition, the tube-screen distance is altered. For miniature radiography the tubescreen distance may be 3 ft., whereas for ordinary radiography it is 56 ft. In the specification of our application Serial No. 604,935 filed July 13, 1945, now U. S. Patent 2,493,161, issued January 3, 1950, a particularly easy and convenient way of converting and automatically re-aligning the apparatus, from miniature to full-size radiography or vice versa, is described. Further details of apparatus suitable for the purpose are given in the specification of co-pending application Serial No. 604,937, filed July 13, 1945, now abandoned.

In radiographic apparatus, and particularly in apparatus designed for mass radiography, it is desirable to have a clear indication that the patient is properly positioned before initiating the exposure.

According to the present invention therefore, the radiographic apparatus comprises a member with which the patient is in contact when correctly ositioned in relation to the remainder of the apparatus, means for supporting said member so that the latter is capable of executing a limited movement under the pressure exerted by the contact of the patient, and switch means responsive to said limited movement to control a circuit indicating when the patient is correctly positioned.

For this purpose a signal light may be provided which is operated when the patient is lean ing against the fluorescent screen or the antiscatter grid or the cassette, so as to give the operator an automatic indication of the patients position. This signal light may be operated by a switch or switches so disposed that a symmetrical pressure in the shoulder region must be. exerted before the switch or switches operate. It is possible and arbitrary, of course, to couple to this signal a further interlock which would lock the controls until the patient pressed against the fiuorescent screen or grid or cassette.

An embodiment of the present invention in which the switch is associated with the antiscatter grid placed in front of the fluorescent screen of apparatus for screen radiography will now be described with reference to the accompanying drawings, in which:

Fig. 1 shows a perspective view of that part of the apparatus aiiected by the present invention.

Fig. 2 shows a fragmentary section in one end position of the grid.

Fig. 3 shows the same section in the other end position of the grid.

Fig. 4 shows a perspective view of a detail.

Fig. 1 shows the immediate housing of the fluorescent screen of an apparatus as described in application 604,937 for miniature screen radiography or normal direct radiography of the chest alternatively. As more fully described and shown in the co-pending application, the screen is mounted on the upper part of a unit comprising the controls and the associated control panel, a platform being provided on which the patient stands with the chest against the screen. In practice, an anti-scatter grid. such as a Lysholm '1 grid is preferably mounted on the patient side of the fluorescent screen, so that when the patient is correctly positioned there is contact between the chest of the patient and the surface of the grid.

As in the construction described and shown in application 604,937, the screen housing I is provided with a slot 2 to receive a card bearing data identifying the patient. The date and possibly other data common to all exposures of a series are provided in a holder 3. The identification card and the date are recorded photographically on the film on which the fluorescent screen image is photographed. The upper part of the housing I is also furnished with tubular inserts which serve for the attachment of a cassette holder whereby a normal cassette can be supported in front of the housing I for direct radiography, as more fully described in application Ser. No. 604,937.

In the construction according to the present invention shown in the accompanying drawings, the fluorescent screen 5 (Figs. 2 and 3) is stationarily mounted in the housing I and the Lysholm grid 6 in its frame 1 i ounted in the surface of the housing I on the tube side of the screen 5. The grid 6 is mounted by means of four corner clips engaging the four corners of the frame I. The bottom clips 8 are secured to the housing I and engage the frame 1 so as to hold the lower edge thereof substantially without play. The top clips are constituted by sliding catches l slidable in brackets 9 secured to the housing I just above the upper edge of the frame 1. The sliding catches Iii are shown in their operative position. When they are retracted the upper edge of the frame I is released and the frame with the grid 5 can be removed. The catches are so disposed that the upper edge of the frame is not clamped against the screen 5 but has a small degree of play, so that the frame i can be displaced towards the screen against spring action by the pressure of the patient against-the grid.

The upper edge of the frame I is engaged from the rear at the centre by a trigger H which is pivoted on a fulcrum pin 12 mounted in a bracket l3 secured to the housing 1 by an anchoring screw it. The trigger H i constantly engaged by a coiled spring 15 which tends to pivot it about the pin 12 so that end of the trigger engaging the frame 2 moves forward to urge the frame 1 against the catches iii. The trigger H is also engaged by a plunger l6 which actuates an electrio switch it, preferably a micro-switch, which is connected in a circuit controlling an indicator lamp ii? on the control panel. If desired, the circuit may be associated with other interlocks which ensure that the apparatus can only be used when all the controls are properly set.

It will be apparent, that in the absence of a patient, the trigger i I assumes the position shown in Fig. 3, whereas when the patient is correctly positioned against the grid 6 the grid and trigger are displaced so that the latter assumes the position shown in Fig. 2. The movement of the trig.- ger it causes corresponding movement of the plunger 26 which operates the switch 18 in a well-known manner.

I claim:

1. Apparatus for miniature radiography comprising a housing including a fluorescent screen, a patient-positioning frame on one side of the screen engageable by a patient, means to rigidly secure one end of the frame to the housing, means to flexibly support the other end of the frame from the housing, a resilient member engaging the frame at the end thereof which is flexibly supported from the housing, and a switch member engaged by the resilient member responsive 4 to limited movement of the patient-positioning frame for controlling a circuit indicating engagement of the member by the patient thereby indicating correct positioning of the patient for exposure.

2. Apparatus for miniature radiography comprising a housing including a fluorescent screen, a patient-positioning frame including an antiscatter grid on one side of the screen engageable by a patient, means to rigidly secure one end of the frame to the housing, means to flexibly support the other end of the frame from the housing, a resilient member engaging the frame at the end thereof which is flexibly supported from the housing, and a switch member engaged by the resilient member responsive to limited movement of the patient-positioning frame for controlling a circuit indicating engagement of the member by the patient thereby indicating correct positioning of the patient for exposure.

3. Apparatus for miniature radiography comprising a housing including a fluorescent screen and'means to photograph the fluorescent screen, means to rigidly secure one end of the screen to the housing, means to flexibly support the other end of the screen from the housing for limited movement in response to pressure applied when a patient is positioned in front of said screen, a resilient member engaging the screen at the end thereof which is flexibly supported from the housing, and a switch member engaged by the resilient member responsive to limited movement of the screen for controlling a circuit indicating en gagement of the screen by the patient thereby indicating correct positioning of the patient for exposure.

ANTHONY NEMET.

REFERENCES Qli'liEB The following references are of record in the file of this patent:

- UNITED STATES PATENTS Number Name Date 1,651,707 Irwig Dec. 6, 1927 2,382,739 Muller Aug. 14, 1945 2,433,129 Land Dec. 23, 1947 

